Reconfigurable PM Machine Windings for Aircraft Voltage Control
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Solution Overview
Problem
Permanent magnet synchronous machines in aerospace applications face design challenges due to significant voltage variations across stator terminals resulting from high speed ranges, leading to inefficiencies in power generation at low and high-speed operations.
Innovation Solution
Aircraft power and propulsion systems with a permanent magnet electrical machine featuring stator windings that can be controllably switched between star and delta configurations, controlled by a system that adjusts the configuration based on operating conditions to stabilize terminal voltage and power demand.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If the electrical machine is optimized for low-speed engine operation, then low-speed power generation capability is improved, but high-speed operation produces undesirably high terminal voltages
Solution Approach 1:
The patent applies the dynamics principle by making the stator winding configuration dynamic and adjustable. The stator windings can be switched between star and delta configurations based on operating conditions. At high speeds, the delta configuration is used to limit voltage and optimize power generation. At low speeds, the star configuration is used to increase voltage and improve power generation capability. This dynamic reconfiguration allows the electrical machine to adapt to varying speed conditions and maintain optimal performance across the entire operating range.
Solution Approach 2:
The patent applies the parameter changes principle by changing the electrical configuration parameters of the stator windings. By switching between star and delta configurations, the electrical parameters (voltage, current, impedance) are adjusted according to the operating speed. This parameter change allows the system to maintain desirable voltage levels at high speeds while improving voltage output at low speeds, thereby resolving the contradiction between low-speed performance and high-speed voltage control.
2Device complexity
If the stator windings are kept in a fixed configuration, then device complexity is reduced, but adaptability to different operating conditions deteriorates
Solution Approach 1:
The patent applies the dynamics principle by making the stator winding configuration dynamic and adjustable. The stator windings can be switched between star and delta configurations based on operating conditions. At high speeds, the delta configuration is used to limit voltage and optimize power generation. At low speeds, the star configuration is used to increase voltage and improve power generation capability. This dynamic reconfiguration allows the electrical machine to adapt to varying speed conditions and maintain optimal performance across the entire operating range.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Stabilizes terminal voltage and power output across varying speed ranges, enhancing efficiency and reducing losses in power electronics by dynamically adjusting stator winding configurations.
Implementation Method 1
With the absence of windings in the rotor of a permanent magnet machine, the internal voltage (or back EMF) in the stator windings changes in proportion to the rotational speed of the rotor.
Data Source
AI summary
Reconfigurable permanent magnet electrical machines and aircraft power and propulsion systems comprising such electrical machines are described. In one aspect, an aircraft power and propulsion system comprises: a gas turbine engine; a permanent magnet electrical machine comprising a rotor drivingly coupled to a spool of the gas turbine engine, and a stator comprising windings controllably switchable between a star configuration and a delta configuration; a DC electrical network; an AC:DC power electronics converter, an AC side of which is connected to terminals of the stator windings of the electrical machine and a DC side of which is connected to the DC electrical network; and a control system. The control system is configured to monitor at least one operating condition of the power and propulsion system and to control the switching of the stator windings between the star configuration and the delta configuration based on the at least one operating condition.